1. Field of the Technique
The presently disclosed technique pertains to in-line explosive trains, and, more particularly, to a dynamic switch for use in an in-line explosive train.
2. Description of the Related Art
This section of this document introduces various aspects of the art that may be related to various aspects of the present invention described and/or claimed below. It provides background information to facilitate a better understanding of the various aspects of the present invention. As the section's title implies, this is a discussion of “related” art. That such art is related in no way implies that it is also “prior” art. The related art may or may not be prior art. The discussion in this section of this document is to be read in this light, and not as admissions of prior art.
The majority of bomb fuzes use an “out-of-line” explosive train to achieve an acceptable level of safety. An out-of-line system is armed by moving the detonator into line with the rest of the explosive train. When unarmed there is a safety barrier between the detonator and the explosive train. An “in-line” system has the detonator always aligned with the explosive train. In-line refers to an uninterrupted explosive train. In-line explosive train systems were first developed for use in nuclear weapons to provide a highly reliable, safe, and precisely timed means of explosive initiation. The technology has matured, and with the introduction of low cost Exploding Foil Initiators (“EFI”), the technology has proliferated beyond nuclear weapon applications.
The inherent safety of the EFI in-line system is derived from the elimination of any pyrotechnics or primary explosives. Energetic materials used are only highly insensitive secondary explosives. Initiation of these energetic materials within the EFI utilizes a specific amplitude and frequency electric pulse. For an in-line fuze, the safe condition is defined when the voltage on the firing capacitor is less than 500 VDC and all safety features are in their safe state. By design, the EFI must be safe for any voltage level of 500 Volts or less directly applied to its detonation contacts.
All Fuze Safety Board's require that special safety precautions be taken when using any in-line detonation system. At a minimum it is required that three safety features be used that will stop the arming of the system and that one of these be dynamic. Dynamic requires that the switch be turned on and off in an oscillatory manor for arming to commence. Designing a switch that will do this is trivial but the Safety community wants the switch to do this without having any free running oscillator, clock, or frequency source dependence. This has proven to be a significant challenge that has yet to be fully solved.
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.